Description : Air refrigeration operates on (a) Carnot cycle (b) Reversed Carnot cycle (c) Rankine cycle (d) Brayton cycle.
Last Answer : Ans: d
Description : Vapour compression refrigeration is some what like (a) Carnot cycle (b) Rankine cycle (c) reversedCamot cycle (d) reversed Rankine cycle
Last Answer : Ans: C
Description : The following cycle is used for air craft refrigeration (a) Brayton cycle (b) Joule cycle (c) Carnot cycle (d) Bell-Coleman cycle (e) Reversed-Brayton cycle.
Last Answer : Answer : e
Description : A refrigerator is working on reversed carnot cycle between temperature of 30°C to –10°C with capacity of 10 tonnes. Calculate. (i) The COP (ii) Define ton of refrigeration (iii) Give the industrial application of refrigeration
Last Answer : (ii) Ton of refrigeration: It is defined as the quantity of heat required to be removed from 1Ton water at 0oC to get ice at 0oC in one day. (iii) Industrial applications of refrigeration ... food stuff such as meat, fruit, fruit juice, vegetables etc. 5. Ice cooling of concrete for dam.
Description : The main feature of Carnot refrigeration cycle is that, it (A) Does not need the addition of external work for its functioning (B) Transfers heat from high temperature to low temperature (C) Accomplishes the reverse effect of the heat engine (D) None of these
Last Answer : (C) Accomplishes the reverse effect of the heat engine
Description : Which of the following has the minimum value of COP for a given refrigeration effect? (A) Reverse Carnot cycle (B) Ordinary vapour-compression cycle (C) Vapour-compression process with a reversible expansion engine (D) Air refrigeration cycle
Last Answer : (D) Air refrigeration cycle
Description : Out of the following refrigeration cycles, which one has the minimum COP (Co-efficient of performance)? (A) Air cycle (B) Carnot cycle (C) Ordinary vapour compression cycle (D) Vapour compression with a reversible expansion engine
Last Answer : A) Air cycle
Description : Efficiency of a Carnot engine is given as 80%. If the- cycle direction be reversed, what will be the value of COP ofreversed Carnot cycle (a) 1.25 (b) 0.8 (c) 0.5 (d) 0.25
Description : Consideration of the creep is the most important in case of the (A) Blades of gas turbine (B) Piston of an I. C. engine (C) Flywheel of steam engine (D) Cycle chain
Last Answer : (A) Blades of gas turbine
Description : Pick out the wrong statement. (A) A refrigeration cycle violates the second law of thermodynamics (B) Refrigeration cycle is normally represented by a temperature vs. entropy plot (C) In a refrigerator, ... (D) One ton of refrigeration is equivalent to the rate of heat absorption equal to 3.53 kW
Last Answer : (A) A refrigeration cycle violates the second law of thermodynamics
Description : Refrigeration cycle (A) Violates second law of thermodynamics (B) Involves transfer of heat from low temperature to high temperature (C) Both (A) and (B) (D) Neither (A) nor (B)
Last Answer : (B) Involves transfer of heat from low temperature to high temperature
Description : Domestic refrigerator usually works on the __________ refrigeration cycle. (A) Carnot (B) Air (C) Absorption (D) vapour-ejection
Last Answer : (C) Absorption
Description : According to Clausis statement of second law of thermodynamics (a) heat can't be transferred from low temperature source to high temperature source (b) heat can be transferred for low temperature to ... to high temperature source without the aid of external energy (e) all of the above.
Last Answer : Answer : d
Description : Most of the centrifugal pumps used in chemical plants are usually __________ driven. (A) Steam (B) Diesel engine (C) Electric motor (D) Gas turbine
Last Answer : (C) Electric motor
Description : Ideal refrigeration cycle is (A) Same as Carnot cycle (B) Same as reverse Carnot cycle (C) Dependent on the refrigerant's properties (D) The least efficient of all refrigeration processes
Last Answer : (B) Same as reverse Carnot cycle
Description : Gas turbine normally employs a constant __________ cycle. (A) Pressure (B) Temperature (C) Volume (D) None of these
Last Answer : (A) Pressure
Description : In a Rankine cycle, regeneration results in higher efficiency because (a) Pressure inside the boiler increases [GATE-2003] (b) Heat is added before steam enters the low pressure turbine (c) ... temperature of heat addition in the boiler increases (d) Total work delivered by the turbine increases
Last Answer : (c) Average temperature of heat addition in the boiler increases
Description : Ammonia-absorption refrigeration cycle requires (a) very little work input (b) maximum work input (c) nearly same work input as for vapour compression cycle (d) zero work input
Last Answer : Ans: a
Description : Pick out the wrong statement. (A) Economy of a multiple effect evaporator is not influenced by the boiling point elevation (B) Two identical cubes of iron and copper will have the same heat ... in the field of refrigeration (D) Finned tube heat exchangers are suitable for heating air by steam
Last Answer : (B) Two identical cubes of iron and copper will have the same heat content under the same conditions of temperature
Description : Co-efficient of performance for a reversed Carnot cycle working between temperatures T1 and T2(T1 > T2) is (A) T2/(T1- T2) (B) T1/(T1- T2) (C) (T1- T2)/T1 (D) (T1- T2)/T2
Last Answer : (A) T2/(T1- T2)
Description : In an ideal refrigeration cycle, the change in internal energy of the fluid is (A) +ve (B) -ve (C) 0 (D) Either of the above three; depends on the nature of refrigerant
Last Answer : (C) 0
Description : Out of the following refrigeration cycles, which one has maximum COP? (A) Air cycle (B) Carnot cycle (C) Ordinary vapor compression cycle (D) Vapor compression with a reversible expansion engin
Last Answer : (B) Carnot cycle
Description : Air-refrigeration cycle (A) Is the most efficient of all refrigeration cycles (B) Has very low efficiency (C) Requires relatively large quantities of air to achieve a significant amount of refrigeration (D) Both (B) and (C)
Last Answer : (D) Both (B) and (C)
Description : Pressure-enthalpy chart is useful in refrigeration. The change in internal energy of an ideal fluid used in ideal refrigeration cycle is (A) Positive (B) Negative (C) Zero (D) Infinity
Last Answer : C) Zero
Description : The co-efficient of performance (COP) of a refrigerating system, which is its index of performance, is defined as the ratio of useful refrigeration to the net work. The units of __________ and COP are the same. (A) Kinematic viscosity (B) Work (C) Temperature (D) None of these
Last Answer : (D) None of these
Description : A jet engine turbine blade is normally manufactured by (A) Forging (B) Shell moulding (C) Investment casting (D) Pressure die casting
Last Answer : (C) Investment casting
Description : The vapour compression refrigerator employs the following cycle (a) Rankine (b) Carnot (c) Reversed Carnot. (d) Brayton
Last Answer : Ans: c
Description : A Bell-Coleman cycle is a reversed of which the following cycles? a. Stirling cycle b. Joule cycle c. Carnot cycle d. Otto cycle
Last Answer : Joule cycle
Description : Which of the following is used in thermal power plant? a. Brayton cycle b. Reversed carnot cycle c. Rankine cycle d. Otto cycle
Last Answer : Rankine cycle
Description : Reversed joule cycle is called (a) Carnot cycle (b) Rankine cycle (c) Brayton cycle (d) Bell Coleman cycle (e) Dual cycle.
Last Answer : Answer : c
Description : In which of the waste heat recovery equipment, the flow of flue gas and air is alternately reversed after a fixed interval of time? (A) Recuperator (B) Regenerator (C) Waste heat boiler (D) None of these
Last Answer : (B) Regenerator
Description : In a refrigeration cycle, the super heating……..C.O.P (a)decreases (b)does not change (c) increases (d)none of the above
Description : Air refrigeration cycle is used in (a) domestic refrigerators (b) gas liquefaction (c)commercial refrigerators (d) Chillers
Last Answer : Ans: b
Description : The change in evaporator temperature in a refrigeration cycle, as compared to change in condenser temperature, influences the value of C.O.P. (a) more (b) less (c) equally. (d) unpredictable
Description : The C.O.P. of a refrigeration cycle with lowering of condenser temperature, keeping the evaporator temperatureconstant, will (a) increase (b) decrease (c) may increase or decrease depending on the type of refrigerant used (d) remain unaffected
Description : Reducing suction pressure in refrigeration cycle (a) lowers evaporation temperature (b) increases power required per ton of refrigeration (c) lowers compressor capacity because vapour is lighter (d) all of the above.
Description : Most of the domestic refrigerators work on the following refrigeration system (a) vapour compression (b) vapour absorption (c) carnot cycle (d) electrolux refrigerator
Description : The C.O.P of a refrigeration cycle with increase in evaporator temperature, keeping condenser temperature constant, will (a) increase (b) decrease (c) remain unaffected (d) may increase or decrease depending on the type of refrigerant used
Description : Under-cooling in a refrigeration cycle (a) increases COP (b) decreases COF (c) COP remains unaltered (d) other factors decide COP
Description : Superheating in a refrigeration cycle (a) increases COP (b) decreases COP (c) COP remains unaltered (d) other factors decide COP
Description : The lower horizontal line of the refrigeration cycle plotted on pressure-enthalpy-diagram represents (a) condensation of the refrigerant vapour (b) evaporation of the refrigerant liquid (c) compression of the refrigerant vapour (d) metering of the refrigerant liquid
Description : In a refrigeration cycle, the flow of refrigerant is controlled by (a) compressor (b) condenser (c) evaporator (d) expansion valve
Description : A refrigeration cycle operates between condenser temperature of + 27°C and evaporator temperature of- 23°C. TheCarnot coefficient of performance of cycle will be (a) 0.2 (b) 1.2 (c) 5 (d) 6
Description : Highest temperature encountered in refrigeration cycle should be (a) near critical temperature of refrigerant (b) above critical temperature (c) atcritica. temperature (d) much below critical temperature
Description : Air refrigeration cycle is used in (a) domestic refrigerators (b) commercial refrigerators (c) air conditioning (d) gas liquefaction
Description : What is the use of flash chamber in a vapour compression refrigeration cycle to improve the COP of refrigeration cycle ?
Last Answer : When liquid refrigerant as obtained from condenser is throttled, there are some vapours. These vapours if carried through the evaporator will not contribute to refrigerating effect. Using a flash ... out in stages. Similarly compression process is also done in two separate compressor stages.
Description : In thermodynamics, a throttling process, also called a _________, is a type of isenthalpic process where a liquid or gas is cooled as it passes from a higher pressure state to a lower pressure state. a. Rankine Process b. Carnot Cycle c. Joule-Thomson process d. Refrigeration process
Last Answer : Joule-Thomson process
Description : Describe with a neat diagram the working of a simple vapour compression refrigeration system. Represent the cycle on P–V and T–S diagram.
Last Answer : Vapour compression refrigeration cycle: The vapor-compression uses a circulating liquid refrigerant as the medium which absorbs and removes heat from the space to be cooled and subsequently rejects that heat elsewhere. Figure shows ... the compressor. P-V Diagram T-S diagram:
Description : One ton of refrigeration capacity is equivalent to the heat removal rate of (A) 50 kcal/hr (B) 200 BTU/hr (C) 200 BTU/minute
Last Answer : (C) 200 BTU/minute
Description : One ton of refrigeration is not equivalent to the heat removal rate of (A) 200 BTU/minute (B) 50 kcal/minute (C) 50 kJ/sec (D) 3.5 KW
Last Answer : (C) 50 kJ/sec